1. Field of the Invention
This invention relates to a casing which encases equipment such as a monitoring camera and has a drain hole.
2. Description of the Related Art
Equipment installed outdoors, for example, a monitoring camera, usually includes a protective casing encasing an equipment body. Such a casing is waterproofed so that rain water can be prevented from penetration or entrance into the casing through fastening screws, connectors for power supply cables or control signal cables, or the like. Furthermore, the casing has a drain hole formed in the bottom thereof in anticipation of deterioration of packing or the like due to outdoor service for a long period of time and resultant penetration of rain water into the casing.
However, the conventional drain hole has a drain passage which has substantially a uniform inner diameter as shown in FIG. 3. As a result, rain water flows through the drain hole into the casing when pelting against the bottom of the casing together with strong winds such as in a typhoon or rainstorm, or when subjected to a strong wind while flowing along the surface of the casing toward the bottom.
Therefore, an object of the present invention is to provide a casing having a drain hole which can prevent rain water from penetrating therethrough into the interior of the casing.
The present invention provides a casing for encasing equipment, comprising a bottom having a drain hole formed therethrough, the drain hole including a first part and a second part having a larger inner diameter than the first part, the second part being open at an underside of the casing.
The above-described casing includes the second part of the drain hole having a larger inner diameter than the first part. The second part of the drain hole is open at the underside of the casing. Consequently, rain water or the like can be prevented from entering the interior of the casing through the drain hole even when pelting against the bottom of the casing together with strong winds such as in a typhoon or rainstorm, or when subjected to a strong wind while flowing along the surface of the casing toward the bottom.
In a preferred form the underside of the casing is formed with a protrusion having a distal end where the second part of the drain hole is open. Since a sufficient depth of the drain hole is ensured, reverse flow of rain water can be prevented more reliably.